The present invention relates to mixed hydroxymethylhydroxyalkyl isocyanurates. Here and hereinafter the terms "hydroxyalkyl" and "(higher) hydroxyalkyl" denote not hydroxymethyl, but only hydroxyalkyl with more than one carbon atom, unless stated otherwise.
Representatives of the trishydroxyalkyl isocyanurates with three identical hydroxyalkyl groups, including trishydroxymethyl isocyanurate, are well known and are used for many purposes. U.S. patent application Ser. No. 588,944, filed June 20, 1975, now U.S. Pat. No. 4,031,040 which is hereby incorporated by reference, discloses the use of trishydroxymethyl isocyanurate as a polyol in the preparation of polyurethanes from a polyol and a polyisocyanate. This has several advantages over other polyols. However, when used for the preparation of polyurethanes, the known trishydroxyalkyl isocyanurates have the drawback that all three hydroxy groups have the same reactivity towards the polyisocyanate, whereas a polyol with hydroxy groups of different reactivity is desirable for the preparation of some polyurethanes. The present invention meets the need of providing polyols that combine the advantages of trishydroxymethyl isocyanurate with the advantages of polyols having hydroxy groups of different reactivity by making available mixed hydroxymethyl-hydroxyalkyl isocyanurates. Polyurethanes prepared from the mixed hydroxymethylhydroxyalkyl isocyanurates of the present invention may be used for the preparation of foams, lacquers, varnishes etc.